From patchwork Tue Dec 24 20:04:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Henderson X-Patchwork-Id: 13920464 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BD18CE77188 for ; Tue, 24 Dec 2024 20:06:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tQB9u-0002ly-Vq; Tue, 24 Dec 2024 15:05:39 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tQB9l-0002jX-9j for qemu-devel@nongnu.org; Tue, 24 Dec 2024 15:05:30 -0500 Received: from mail-pl1-x635.google.com ([2607:f8b0:4864:20::635]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1tQB9j-0002Ws-MR for qemu-devel@nongnu.org; Tue, 24 Dec 2024 15:05:29 -0500 Received: by mail-pl1-x635.google.com with SMTP id d9443c01a7336-2166f1e589cso67033785ad.3 for ; Tue, 24 Dec 2024 12:05:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1735070726; x=1735675526; darn=nongnu.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=iOzpxqZ9VNfy3l9f3NLQHzVfPYu5zW7VkQL9KwFwxnA=; b=xcLWc0LJluNu9CiKwHB1b/v9WGr0iy/kgAYBBZ+mTVb6eIkwlSIpvg/ATl8PDZ3aoL OSP4HLFLoJ/pmYZHtDCQiaCYxJ5gVTrbIJGOVSM8akb0oIkNALvNevi4ljpkYU6amBHm i4YynXDzU0joKD+Onsi7bcjcXzlOAjHmaMgVTL4+Led/2DKhXOB/3eTzU5PJqZpKL+Cv SBYfKnx6Jx161YUUl0qMZgRbP5lreHVeqt5MmbawIsEIen5q9GauClEGagOkf1SkKmHw xYMP/ZLHhgLd4xvKRLfl3N2SC0O6KmL1U6VfjndhAsCTU6ie/C/KsAGd7lMHokn4BCSx M+2w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1735070726; x=1735675526; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=iOzpxqZ9VNfy3l9f3NLQHzVfPYu5zW7VkQL9KwFwxnA=; b=SNfLUhF5nN2rSGa9SwHrZVfMmXNNVaV3EtNyn6lnbBJ4HL+SJ7qZvoPToatoJasT9Z z8YHkzQt3vpkU8KyXkYaM+16fmT++H07Jy4GLV4GQDFTfvQ+yOza4AFS1adP2sOtWG7K aIbor6cty7yL0V4p85gtECMRD/6h/sObLr1z60llmzwj0vaoIvQ3ufrYD3z/GBpC66v0 gkRmFPYew52k/Kj0x8GrADWK7Rl8KiDpuLZ2XZc6IU6H4MyKFj7F4aMvVg/rXlRLAYdp nI96LhzLRsHpLnY1kcgMr8G4KKMf0vFr6i7fDgI9laKfXoyOz+WMVWxryiYCdVOepg/X /hoQ== X-Gm-Message-State: AOJu0YyPDLpwtdlqvhs2B0tEZ6hYcslk/jMrGnAqMpgp2amfYcqxgH8X hD/TIroyi1+40GQmkgGoZM3+VmMc9HiBkhKvdOwVdQkS18hhyST2CYKQiO0/D9rDP9CjVV5xVY0 af54= X-Gm-Gg: ASbGncv7psoRQMr7filob/BdTdEXhOJ6DN/kNSEUAl+Xu18RyYI8fBPgxW1W++ISlcG WD3FdDOXBFVrJu+y21dm0S+Rudm1A2Sy8gB5guoKBbcxq+8m4ZFj9Z30kcXebxBUsIzyRS2Pq4U 7y01TWK2s2AFICSOd9vnN3ADcX+cLgyMA+9fJ9l3rcE8qsLVgw4Xmu5JzY8jCzD1gW6qV7a61QB cEBQ6OHx8ivna6tWac7zEa8d1sTclXtZuI8diqG5JzCqtvshDWlMRHn/Lj7gjsGGs6nMNTurm0M KLg8NnhJXO+neIJgy5t2Az4fpw== X-Google-Smtp-Source: AGHT+IFX+rO/BfMWuku7Q9xzFRU3p3Nn4e8mGAzI0HIjaO78nybOXFotFdlMEt5qPX4z7c+1UkiWbA== X-Received: by 2002:a05:6a21:3103:b0:1e1:a932:4a40 with SMTP id adf61e73a8af0-1e5e043f517mr25728596637.4.1735070726119; Tue, 24 Dec 2024 12:05:26 -0800 (PST) Received: from stoup.. (syn-156-019-246-023.biz.spectrum.com. [156.19.246.23]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-72aad8fb895sm10027159b3a.162.2024.12.24.12.05.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Dec 2024 12:05:25 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Pierrick Bouvier Subject: [PULL 04/72] tcg/optimize: Split out fold_affected_mask Date: Tue, 24 Dec 2024 12:04:13 -0800 Message-ID: <20241224200521.310066-5-richard.henderson@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241224200521.310066-1-richard.henderson@linaro.org> References: <20241224200521.310066-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::635; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x635.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org There are only a few logical operations which can compute an "affected" mask. Split out handling of this optimization to a separate function, only to be called when applicable. Remove the a_mask field from OptContext, as the mask is no longer stored anywhere. Reviewed-by: Pierrick Bouvier Signed-off-by: Richard Henderson --- tcg/optimize.c | 42 +++++++++++++++++++++++++++--------------- 1 file changed, 27 insertions(+), 15 deletions(-) diff --git a/tcg/optimize.c b/tcg/optimize.c index 453e8c43bd..6757fe0036 100644 --- a/tcg/optimize.c +++ b/tcg/optimize.c @@ -64,7 +64,6 @@ typedef struct OptContext { QSIMPLEQ_HEAD(, MemCopyInfo) mem_free; /* In flight values from optimization. */ - uint64_t a_mask; /* mask bit is 0 iff value identical to first input */ uint64_t z_mask; /* mask bit is 0 iff value bit is 0 */ uint64_t s_mask; /* mask of clrsb(value) bits */ TCGType type; @@ -1047,7 +1046,6 @@ static bool fold_const2_commutative(OptContext *ctx, TCGOp *op) static bool fold_masks(OptContext *ctx, TCGOp *op) { - uint64_t a_mask = ctx->a_mask; uint64_t z_mask = ctx->z_mask; uint64_t s_mask = ctx->s_mask; @@ -1059,7 +1057,6 @@ static bool fold_masks(OptContext *ctx, TCGOp *op) * type changing opcodes. */ if (ctx->type == TCG_TYPE_I32) { - a_mask = (int32_t)a_mask; z_mask = (int32_t)z_mask; s_mask |= MAKE_64BIT_MASK(32, 32); ctx->z_mask = z_mask; @@ -1069,6 +1066,19 @@ static bool fold_masks(OptContext *ctx, TCGOp *op) if (z_mask == 0) { return tcg_opt_gen_movi(ctx, op, op->args[0], 0); } + return false; +} + +/* + * An "affected" mask bit is 0 if and only if the result is identical + * to the first input. Thus if the entire mask is 0, the operation + * is equivalent to a copy. + */ +static bool fold_affected_mask(OptContext *ctx, TCGOp *op, uint64_t a_mask) +{ + if (ctx->type == TCG_TYPE_I32) { + a_mask = (uint32_t)a_mask; + } if (a_mask == 0) { return tcg_opt_gen_mov(ctx, op, op->args[0], op->args[1]); } @@ -1305,8 +1315,9 @@ static bool fold_and(OptContext *ctx, TCGOp *op) * Known-zeros does not imply known-ones. Therefore unless * arg2 is constant, we can't infer affected bits from it. */ - if (arg_is_const(op->args[2])) { - ctx->a_mask = z1 & ~z2; + if (arg_is_const(op->args[2]) && + fold_affected_mask(ctx, op, z1 & ~z2)) { + return true; } return fold_masks(ctx, op); @@ -1331,7 +1342,9 @@ static bool fold_andc(OptContext *ctx, TCGOp *op) */ if (arg_is_const(op->args[2])) { uint64_t z2 = ~arg_info(op->args[2])->z_mask; - ctx->a_mask = z1 & ~z2; + if (fold_affected_mask(ctx, op, z1 & ~z2)) { + return true; + } z1 &= z2; } ctx->z_mask = z1; @@ -1709,8 +1722,8 @@ static bool fold_extract(OptContext *ctx, TCGOp *op) z_mask_old = arg_info(op->args[1])->z_mask; z_mask = extract64(z_mask_old, pos, len); - if (pos == 0) { - ctx->a_mask = z_mask_old ^ z_mask; + if (pos == 0 && fold_affected_mask(ctx, op, z_mask_old ^ z_mask)) { + return true; } ctx->z_mask = z_mask; ctx->s_mask = smask_from_zmask(z_mask); @@ -1777,8 +1790,8 @@ static bool fold_exts(OptContext *ctx, TCGOp *op) ctx->z_mask = z_mask; ctx->s_mask = s_mask; - if (!type_change) { - ctx->a_mask = s_mask & ~s_mask_old; + if (!type_change && fold_affected_mask(ctx, op, s_mask & ~s_mask_old)) { + return true; } return fold_masks(ctx, op); @@ -1819,8 +1832,8 @@ static bool fold_extu(OptContext *ctx, TCGOp *op) ctx->z_mask = z_mask; ctx->s_mask = smask_from_zmask(z_mask); - if (!type_change) { - ctx->a_mask = z_mask_old ^ z_mask; + if (!type_change && fold_affected_mask(ctx, op, z_mask_old ^ z_mask)) { + return true; } return fold_masks(ctx, op); } @@ -2482,8 +2495,8 @@ static bool fold_sextract(OptContext *ctx, TCGOp *op) s_mask |= MAKE_64BIT_MASK(len, 64 - len); ctx->s_mask = s_mask; - if (pos == 0) { - ctx->a_mask = s_mask & ~s_mask_old; + if (pos == 0 && fold_affected_mask(ctx, op, s_mask & ~s_mask_old)) { + return true; } return fold_masks(ctx, op); @@ -2843,7 +2856,6 @@ void tcg_optimize(TCGContext *s) } /* Assume all bits affected, no bits known zero, no sign reps. */ - ctx.a_mask = -1; ctx.z_mask = -1; ctx.s_mask = 0;